There long has been a desire in the deodorant and cosmetic industry for a dry, aesthetically pleasing product which is substantially non-toxic and free flowing, and can be impregnated, coated and otherwise delivered to various substrates and formulations for use in various and sundry products.
There have been various attempts in the prior art to arrive at such free flowing, easily formulating products. For example, the 3M Company in its encapsulated products/3M Product Information Bulletin, entitled "3M Microcapsules Mineral Oil/180 Microns" bearing a number of 77-9802-7051-4 describes a microencapsulated mineral oil, which microcapsules are reported to have a diameter of 180 microns and are described as soft clumps of grainy, white powder with a slightly grainy feel. The microencapsulated core material is USP grade mineral oil and when pressure is applied the microcapsules break and mineral oil is released. This product has clumps or agglomerates of individual microcapsules and is stated to contain a maximum of 12 weight percent of free (non-microencapsulated) mineral oil. This product also contains 400 parts per million (maximum) of aqueous extractable formaldehyde. This product bulletin also includes the further designation of "Resin FDA CRNCS No. R0012291". The microencapsulating cell wall material, or shell material, is a urea-formaldehyde resin. The material corresponding to this 3M Product Information Bulletin does not have the free-flowing characteristics of the microcapsules produced in accordance with this invention.
U.S. Pat. No. 4,808,408, issued to R. W. Baker, is directed to preparation of microencapsulated hydrophobic materials, including fragrances. Also there is disclosed in Example 5 use of a "Gantrez" resin as a pharmaceutical vehicle to produce a resulting cream containing insect repellant.
U.S. Pat. No. 4,082,688, issued to S. Egawa, is directed to a process for producing microcapsules having a gelatin cell wall material wherein the microcapsule wall is produced by coacervation and hardened using at least two kinds of chemical hardening agents in a hardening step(s).
U.S. Pat. No. 3,691,270, issued to R. Charle et al, is directed to microencapsulation of make-up removing or treating compositions which are incorporated into a cosmetic cream or incorporated in a flexible support described as an aloe vera polymer support.
U.S. Pat. No. 4,205,060, issued to H. G. Monsimer, teaches in its Example 5 use of hydrolyzed "Gantrez AN169" copolymer of methyl vinyl ether and maleic anhydride to microencapsulate medicaments.
It will be clearly evident that the microcapsules of the present invention possess a desirable combination of properties not possessed by the prior art patents and the product bulletin referred to above.